The present invention relates to an image recording apparatus, and more particularly, to an image recording apparatus which records image via an ink-jet method.
The image recording apparatus employing the ink-jet method (hereinafter referred to as an ink-jet image recording apparatus) has been known in the prior art as an image recording apparatus which works for a large item small volume production, according to circumstances. The ink-jet image recording apparatus jets ink droplets through nozzles, provided on the surface of a recording head, which faces a recording medium, after which the deposited ink droplets are fixed on the recording medium to record the image. Since the ink-jet image recording apparatus does not use a plate making process, differing from conventional image recording means which prints the image via a gravure printing method or a flexographic printing method, a characteristic of ink-jet image recording apparatus is that they quickly serve for a small volume production with ease. Further, the ink-jet image recording apparatus easily records color images using various colored inks at low noise, which is an advantage.
In recent years, an ink-jet recording apparatus employing photo-curable ink has become well known as the image recording apparatus which is able to print the image on various types of the recording media. Using the photo-curable ink which includes an initiator having predetermined sensitivity to ultraviolet rays, the ink-jet recording apparatus radiates the ultraviolet rays onto the photo-curable ink deposited on the recording medium, and thereby the photo-curable ink is hardened and fixed on the recording medium. In the ink-jet image recording apparatus employing the photo-curable ink, after the ink droplets are deposited on the recording medium, the ink droplets are hardened at once by the ultraviolet radiation. That is, since the ink-droplets scarcely penetrate through or bleed on the recording medium, the image can be recorded onto not only a normal sheet but also recording medium such as a plastic or metallic material which does not include an image receiving layer, and does not absorb the ink.
When the image is recorded on the recording medium having the image recording layer, most of the ink is absorbed by the recording medium, however, when the image is recorded on a recording medium not having the image recording layer, the deposited ink droplets are hardened and fixed as soon as the light rays are radiated, that is, the deposited ink droplets are not absorbed by the recording medium so that they remain on the surface of the recording medium to be hardened, forming a raised surface.
When the amount of deposited ink droplets is relatively large, bleeding results between adjacent droplets before curing, and thereby a raised surface of a smooth hard coating having lustrous reflection is generated on the surface of the recording medium. On the other hand, when the amount of deposited ink droplets is relatively small, a hard coating having an irregular surface with no reflecting surface is generated on the surface of the recording medium, resulting in no lustrous reflection. Such reflection caused by the amount of the deposited ink droplets is significantly apparent, when ink including a large amount of pigment is used.
When there is a hard coating featuring different smoothness on the surface of the recording medium, that is, on the image, the image is visually observed as an uneven reflective surface, which causes image deterioration over the total image, resulting in not precise image recording, which is a problem.
Concerning the technology for solving the uneven reflective surface generated on the recording medium, the technology is well known wherein the surface is laminated after image recording (See Patent Documents 1 and 2).
Patent Document 1: Japanese Tokkouhei 2-14912
Patent Document 2: Japanese Tokkaihei 9-70960
As described above, the merit of the image recording apparatus which records the image by an ink-jet method using photo-curable ink is that the image can be recorded on various types of recording media. However, if laminated finishing is conducted after the image is recorded, it is necessary that a special recording medium having a thermoplastic resin layer is used, therefore, the merit of ink-jet image recording apparatus, which can record the image on various types of recording media, is reduced, which is a problem.
Additionally, in order to conduct laminated finishing after image recording, a laminate finishing device must be incorporated in the image recording apparatus, which results in a complicated and larger sized apparatus, as well as a rise in the cost of the apparatus. Further, in order to conduct laminated finishing after-image recording, laminate finishing is conducted on the total surface of the recording medium, but as described above, when the image is recorded via photo-curable ink, an ink surface is raised and the reflection is generated on only the surface on which a relatively large amount of ink droplets are deposited, therefore there is no need to conduct laminating. Accordingly, if lamination is conducted on the total surface, a material for lamination utilized on the surface on which lamination is not necessary, results in waste of material and raised cost.